Auto merge of #883 - micbou:cs-completer-zero-column-diagnostic, r=pu…

…remourning

[READY] Handle zero column diagnostic from OmniSharp

The OmniSharp server sometimes incorrectly returns diagnostics with a column number of 0 while lines and columns are supposed to be 1-indexed. This causes the following error:
```
Traceback (most recent call last):
  File "C:\Users\micbou\projects\YouCompleteMe\third_party\ycmd\third_party\bottle\bottle.py", line 862, in _handle
    return route.call(**args)
  File "C:\Users\micbou\projects\YouCompleteMe\third_party\ycmd\third_party\bottle\bottle.py", line 1740, in wrapper
    rv = callback(*a, **ka)
  File "C:\Users\micbou\projects\YouCompleteMe\third_party\ycmd\ycmd\..\ycmd\watchdog_plugin.py", line 108, in wrapper
    return callback( *args, **kwargs )
  File "C:\Users\micbou\projects\YouCompleteMe\third_party\ycmd\ycmd\..\ycmd\hmac_plugin.py", line 70, in wrapper
    body = callback( *args, **kwargs )
  File "C:\Users\micbou\projects\YouCompleteMe\third_party\ycmd\ycmd\..\ycmd\handlers.py", line 70, in EventNotification
    event_handler )( request_data )
  File "C:\Users\micbou\projects\YouCompleteMe\third_party\ycmd\ycmd\..\ycmd\completers\cs\cs_completer.py", line 214, in OnFileReadyToParse
    self._diagnostic_store = DiagnosticsToDiagStructure( diagnostics )
  File "C:\Users\micbou\projects\YouCompleteMe\third_party\ycmd\ycmd\..\ycmd\completers\cs\cs_completer.py", line 611, in DiagnosticsToDiagStructure
    structure[ diagnostic.location_.filename_ ][
AttributeError: 'NoneType' object has no attribute 'filename_'
```
See ycm-core/YouCompleteMe#2846 (comment). We assume the column number is 1 in that case.

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ycmd/completers/cs/cs_completer.py

@@ -678,8 +678,12 @@ def _IndexToLineColumn( text, index ):
 
 
 def _BuildLocation( request_data, filename, line_num, column_num ):
-  if line_num <= 0 or column_num <= 0:
+  if line_num <= 0:
     return None
+  # OmniSharp sometimes incorrectly returns 0 for the column number. Assume the
+  # column is 1 in that case.
+  if column_num <= 0:
+    column_num = 1
   contents = utils.SplitLines( GetFileContents( request_data, filename ) )
   line_value = contents[ line_num - 1 ]
   return responses.Location(

ycmd/tests/cs/diagnostics_test.py

@@ -62,7 +62,6 @@ def Diagnostics_ZeroBasedLineAndColumn_test( app ):
   with WrapOmniSharpServer( app, filepath ):
     contents = ReadFile( filepath )
 
-    results = {}
     for _ in ( 0, 1 ):  # First call always returns blank for some reason
       event_data = BuildRequest( filepath = filepath,
                                  event_name = 'FileReadyToParse',
@@ -100,7 +99,6 @@ def Diagnostics_WithRange_test( app ):
   with WrapOmniSharpServer( app, filepath ):
     contents = ReadFile( filepath )
 
-    results = {}
     for _ in ( 0, 1 ):  # First call always returns blank for some reason
       event_data = BuildRequest( filepath = filepath,
                                  event_name = 'FileReadyToParse',
@@ -143,7 +141,6 @@ def Diagnostics_MultipleSolution_test( app ):
     with WrapOmniSharpServer( app, filepath ):
       contents = ReadFile( filepath )
 
-      results = {}
       for _ in ( 0, 1 ):  # First call always returns blank for some reason
         event_data = BuildRequest( filepath = filepath,
                                    event_name = 'FileReadyToParse',
@@ -173,3 +170,41 @@ def Diagnostics_MultipleSolution_test( app ):
                              } ),
                            } )
                        } ) ) )
+
+
+@SharedYcmd
+def Diagnostics_HandleZeroColumnDiagnostic_test( app ):
+  filepath = PathToTestFile( 'testy', 'ZeroColumnDiagnostic.cs' )
+  with WrapOmniSharpServer( app, filepath ):
+    contents = ReadFile( filepath )
+
+    for _ in ( 0, 1 ):  # First call always returns blank for some reason
+      event_data = BuildRequest( filepath = filepath,
+                                 event_name = 'FileReadyToParse',
+                                 filetype = 'cs',
+                                 contents = contents )
+
+      results = app.post_json( '/event_notification', event_data ).json
+
+    assert_that( results,
+                 contains(
+                     has_entries( {
+                       'kind': equal_to( 'ERROR' ),
+                       'text': contains_string(
+                           "Unexpected symbol `}'', "
+                           "expecting `;'', `{'', or `where''" ),
+                       'location': has_entries( {
+                         'line_num': 3,
+                         'column_num': 1
+                       } ),
+                       'location_extent': has_entries( {
+                         'start': has_entries( {
+                           'line_num': 3,
+                           'column_num': 1,
+                         } ),
+                         'end': has_entries( {
+                           'line_num': 3,
+                           'column_num': 1,
+                         } ),
+                       } )
+                     } ) ) )

ycmd/tests/cs/testdata/testy/ZeroColumnDiagnostic.cs

@@ -0,0 +1,3 @@
+class Class{
+    int Method()
+}